#include "CornellBox.h"
#include "DiffuseLight.h"
#include "Application.h"
#include <thread>
namespace RayTracer 
{
	void CornellBoxSample::Init()
	{
		mImageParam = ImageParam(800, 500, "CornellBox.png");
		lookfrom = vec3(278, 278, -800);
		lookat = vec3(278, 278, 0);
		fov = 40.0;
		background = vec3(0.0);
		upColor = vec3(0.5, 0.7, 1.0);
		downColor = vec3(1.0);
		curIndex = 0.0;
		isGenerate = false;
		left = 278;
		right = 278;
		metalColor = vec3(1.0, 0.0, 0.0);
		roughness = 0.3;
	}

	void CornellBoxSample::Render()
	{
		auto red = std::make_shared<Lambertian>(vec3(.65, .05, .05));
		auto white = std::make_shared<Lambertian>(vec3(.73, .73, .73));
		auto green = std::make_shared<Lambertian>(vec3(.12, .45, .15));
		auto light = std::make_shared<DiffuseLight>(vec3(15, 15, 15));
		auto metal = std::make_shared<Metal>(metalColor,0.3);
		auto glass = std::make_shared<Glass>(1.5);
		world.add(std::make_shared<YZ_Rect>(0, 555, 0, 555, -180, green));
		world.add(std::make_shared<YZ_Rect>(0, 555, 0, 555, 730, red));
		world.add(std::make_shared<XZ_Rect>(-180, 730, 0, 555, 0, white));
		world.add(std::make_shared<XZ_Rect>(-180, 730, 0, 555, 555, white));
		world.add(std::make_shared<XY_Rect>(-180, 730, 0, 555, 555, white));
		world.add(std::make_shared<Box>(vec3(130, 0, 65), vec3(295, 165, 230), white));
		world.add(std::make_shared<Box>(vec3(265, 0, 295), vec3(430, 400, 460), white));
		world.add(std::make_shared<Sphere>(vec3(223,278,0),100.0, metal));

		int width = mImageParam.mWidth;
		int height = mImageParam.mHeight;
		camera = Camera(lookfrom, lookat, fov);

		uint8_t* pixels = new uint8_t[width * height * 3];
		int index = 0;
		for (int j = height - 1; j >= 0; j--) {
			for (int i = 0; i < width; ++i) {
				vec3 color = vec3(0.0f);
				for (int s = 0; s < samples_per_pixel; s++)
				{
					auto u = (i + Random01()) / (width - 1);
					auto v = (j + Random01()) / (height - 1);
					Ray r = camera.GetRay(u, v);
					color += RayColor(r ,world, maxDepth);
				}
				auto scale = 1.0 / samples_per_pixel;
				color *= scale;

				GammaCorrect(color);
				pixels[index++] = static_cast<uint8_t>(256 * clamp(color.r, 0.0, 0.999));
				pixels[index++] = static_cast<uint8_t>(256 * clamp(color.g, 0.0, 0.999));
				pixels[index++] = static_cast<uint8_t>(256 * clamp(color.b, 0.0, 0.999));
				curIndex++;
			}
		}
		Utils::SaveImage(("Images/" + mImageParam.mName).c_str(), width, height, 3, pixels);
		isGenerate = true;
	}

	void CornellBoxSample::ImGui()
	{
		ImGui::Text(u8"Cornell Box - skylight");
		ImGui::Checkbox(u8"Normal", &isNormal);
		if (isNormal)
		{
			samples_per_pixel = 1;
		}
		else
		{
			ImGui::SliderInt(u8"Spp", &samples_per_pixel, 1, 500);
		}
		ImGui::SliderInt(u8"MaxDepth", &maxDepth, 1, 50);
		ImGui::Separator();

		if (ImGui::CollapsingHeader(u8"Sky Color"))
		{
			ImGui::ColorEdit3(u8"High", &upColor[0]);
			ImGui::ColorEdit3(u8"Low", &downColor[0]);
		}
		ImGui::Separator();
		if (ImGui::CollapsingHeader(u8"Camera"))
		{
			ImGui::InputFloat3(u8"Camera Position", &lookfrom[0]);
			ImGui::SliderFloat("Fov", &fov, 20.0, 180.0);
		}
		ImGui::Separator();

		auto w = (float)mImageParam.mWidth;
		auto h = (float)mImageParam.mHeight;
		auto progress = ((float)curIndex / (w*h));
		ImGui::ProgressBar(progress);
		ImGui::Separator(); 
		if (ImGui::Button(u8"Generate")) {
			std::thread t = std::thread([=]() {
				Render();
				});
			t.detach();
		}
		if (isGenerate)
		{
			auto mTexHandle = Utils::LoadTexture(("Images/" + mImageParam.mName).c_str());
			Application::GetInstance()->SetTexHandle(mTexHandle);
			isGenerate = false;
			curIndex = 0;
			world.clear();
		}
	}

	void CornellBoxSample::ShutDown()
	{
		Application::GetInstance()->SetTexHandle(0);
	}

	vec3 CornellBoxSample::RayColor(const Ray& r, const vec3& background, const Hitable& world, int depth)
	{
		HitRecord rec;

		if (depth <= 0)
			return vec3(0, 0, 0);

		if (!world.Hit(r, 0.001, infinity, rec))
			return background;

		Ray scattered;
		vec3 attenuation;
		vec3 emitted = rec.matPtr->Emitted(rec.u, rec.v, rec.position);

		if (!rec.matPtr->Scatter(r, rec, attenuation, scattered))
			return emitted;

		return emitted + attenuation * RayColor(scattered, background, world, depth - 1);
	}

	vec3 CornellBoxSample::RayColor(const Ray& r, const Hitable& world, int depth)
	{
		HitRecord rec;
		if (depth <= 0) return vec3(0.0f);
		if (world.Hit(r, 0.001, infinity, rec))
		{
			vec3 res;
			if (isNormal)
			{
				res = 0.5f * (rec.normal + vec3(1.0f));
			}
			else
			{
				Ray scattered;
				vec3 attenuation;
				if (rec.matPtr->Scatter(r, rec, attenuation, scattered))
					return attenuation * RayColor(scattered, world, depth - 1);
				return vec3(1.0f);
			}
			return res;
		}

		vec3 unit_direction = glm::normalize(r.direction());
		auto t = 0.5f * (unit_direction.y + 1.0f);
		return (1.0f - t) * downColor + t * upColor;
	}
}